Decomposition and Nutrient Release Dynamics of Shoot Phytomass of Cover Crops in the Recôncavo Baiano

AUTOR(ES)
FONTE

Rev. Bras. Ciênc. Solo

DATA DE PUBLICAÇÃO

10/07/2017

RESUMO

ABSTRACT Evaluating the decomposition dynamics of vegetative residues from cover crops can provide a better understanding of nutrient release, which is fundamental when choosing a species that is adapted to local conditions. The objective of this study was to evaluate the decomposition rates and nutrient release dynamics of the shoot phytomass of different cover crops that have potential for agricultural use in the Recôncavo Baiano, Brazil. Crop residues of the following species were analyzed: sunn hemp (Crotalaria juncea L.) - CROT; velvet bean (Mucuna aterrima L.) - MUC; lab lab (Dolichos lab lab L.) - LAB; jack bean (Canavalia ensiformis [L.] DC.) - JB; white lupin (Lupinus albus L.) - WLUP; and Guinea grass (Urochloa maxima (Jacq.) R. Webster) - GRAS. The experiment was conducted in a randomized block design with four replications. The decomposition and nutrient release dynamics were evaluated using litter bags, and the remaining dry matter and the nutrient content of litter from each cover crop were quantified. The accumulation of macronutrients in the phytomass was in the following order: N > K > Ca > Mg > P > S. The highest decomposition rates of the phytomass occurred in the species JB, with half-life (t1/2) of 36 days, and GRAS, with t1/2 of 41 days. K was the element with the shortest t1/2, suggesting a rapid transfer rate to the soil. Organic residues from the CROT and WLUP cover crops had lower decomposition rates and are, therefore, recommended for protecting soil in the region. Sunn hemp, unlike WLUP, also had residue of high chemical quality and, thus, it is an excellent nutrient recycler. Jack bean released nutrients into the soil the fastest due to its rapid decomposition rate; therefore, it is not recommended for ground cover.

Documentos Relacionados